Cold War-era chills. Tourists welcome.

An underground Soviet nuclear bomb shelter is remade into a museum.

MOSCOW — Deep underground in a Cold War-era nuclear bomb shelter, guide Alexei Alexandrov did his best to set a spooky mood, starting with his 1960s Soviet army uniform.

"Please don't split away from the group," he somberly warned visitors to the labyrinth of tunnels shaped into cavernous rooms and lengthy hallways, "or you may get lost in the dark and end up shot by a guard by mistake."

At the budding Moscow tourist attraction called the Confrontation Cold War Museum, historical remembrance and a touch of make-believe mix in an ambiguous but thought-provoking cocktail.

With Washington and Moscow recently trading harsh rhetoric and some analysts warning of a possible slide back toward Cold War attitudes, the shelter serves as a reminder of what that period was like -- and of the fact that similar facilities still function in both countries despite the disappearance of old fears.

The still-unfinished museum doesn't exactly preach. But it aims to send a message. A sign in the entryway declares: "It's important which questions a person asks himself after visiting the complex, which fears worry him, and what he's pondering."

Also known as the Tagansky Underground Command Center, the 75,000-square-foot facility was built 200 feet below ground level as a communications complex meant to survive a U.S. nuclear attack on Moscow. Work on it began in 1952, when Stalin was still Soviet dictator, and it went into service four years later.

The site was in operation through the 1970s, with a staff of 2,500, of whom 1,500 could be on duty at any one time. In the event of a nuclear war, it would have been sealed, with enough stored food for three months, and systems to purify the air. A planned 1980s renovation was abandoned as tensions between the Soviet Union and the West eased, and the site was declassified in 1995.

Now the whole thing has been bought by a private firm, which is converting it to a museum and entertainment complex that mixes advocacy of world peace with displays of Russian patriotism, and what sometimes seems like a touch of nostalgia for Soviet power.

The addition of more displays to enhance the atmosphere is planned. But the mostly empty rooms and hallways, with some half-century-old communications equipment and a variety of Soviet-era posters, themselves evoke a chill. The wall posters include one that is almost touching in its naivete, labeled "Actions of a Soldier During the Flash of a Nuclear Explosion." It shows the mushroom cloud of a nuclear blast, one soldier hiding behind a tree stump and others in trenches.

During the tour, Alexandrov painted a picture of a virulently anti-communist 1950s America that had demonstrated, in Hiroshima and Nagasaki, Japan, that it was "ready to use nuclear weapons against civilian populations."

"They didn't want to talk to us at the time. Instead, they were quite willing to 'destroy the hydra of communism in its lair,' " he told the group of university students and young businesspeople. "It was life under gun sights. The threat was so imminent that our leadership could only have three or four minutes to make a decision."

Visitors were encouraged to wear olive-green Soviet army ponchos for the tour, and Alexandrov demonstrated the use of a gas mask and a 1960s Geiger counter still in working condition.

White respiratory face masks were handed out as part of the atmospherics, and some wore them while posing for souvenir snapshots. Each visitor was given a bright red USSR Defense Ministry pass with their name and a mug shot of someone wearing a gas mask. The tour also included a Cold War-era military rations meal consisting of buckwheat porridge with canned stewed beef and a shot of vodka.

Andrei Kvyk, 21, a student at the Moscow Construction Institute, said being in the shelter gave him "the creeps."

"They say that this is all a thing of the past and that the Cold War is over," he said. "But I don't think that's the case. I am sure facilities like this still exist in Moscow and across the country and are on combat duty every second. I am sure the Cold War was never over. They are lying to us."

The complex was constructed with techniques similar to that used to drill subway tunnels, and walking through it feels like a journey through huge pipes. The largest rooms, built in 30-foot-diameter tunnels, have arched ceilings. The old floors have been ripped out, and in many places one walks on a mix of soil and debris. In a few spots, water drips ominously.

The complex has tunnels linking it to the Moscow subway, which is even older, and in certain areas the roar of trains can be clearly heard.

"It is so spooky -- these tunnels, this porridge, this damp air 60 meters under the ground," said Yana Arutyunova, 25, a market researcher who joined the tour. "People in the tunnels look like ghosts of the past. You can't but feel danger here. Everything was removed at some point, all the equipment, but you can still feel this concentrated cold fear permeating the air."